The invention relates to a lamellar or strip-shaped floor marking, in particular for means of transportation, very particularly for airplanes, having a photoluminescent layer on which covering elements which appear dark in comparison with the luminous layer and which serve as a directional indication are arranged in such a way that acute-angled markings pointing in a direction are formed.
It is known to affix lamellar or strip-shaped floor markings having a photoluminescent layer in airplanes. By means of daylight or the illumination in the airplane cabin, the photoluminescent layer is made to glow. This glow continues for a long period of time when the floor marking is no longer being illuminated. In the case of an accident, airplane passengers can orient themselves even in darkness by means of these glowing floor markings. An external illumination, which is complex and fault-prone, is not required.
These floor markings indicate escape routes. In this case there are also no particular problems if the airplane, as is conventional, is provided with emergency exits at the front and rear end of the airplane cabin (and usually also over the wings). In that case, it is not necessarily a matter of finding the nearest emergency exit in the case of an accident but rather, led by the glowing floor markings, of following the other passengers to the nearest exit. However, it is a different proposition if the airplane has a so-called “dead end”, that is to say if, for example, no emergency exit is provided at the rear end. There is then the danger that in the case of an accident passengers follow the floor markings in the wrong direction, namely to the end of a cabin not provided with an emergency exit. In order to avoid this, it is known to affix opaque markings in triangular form on the floor markings, the tip of the triangle pointing in the direction of the escape route. Such dark markings can be created by applying a coating, for example. The applied coating on the one hand prevents the photoluminescent layer underneath from being “charged” by incident light. On the other hand, light that is nevertheless emitted therefrom is absorbed by the markings. These markings usually have a distance between them of approximately 50 cm. A closer distance is clearly considered not to be expedient, because in this case there is no longer enough glowing surface of the floor marking available.
A problem now occurs if a passenger wishes to observe the marking in order to see in which direction the tip of the triangle is pointing. Due to the darkness, the cone cells of the retina of the eye, which impart color vision and only have a low light sensitivity, do not impart a sense of sight. This is only the case for the rod cells, which are active in the process of seeing light and dark and have a high light sensitivity. However, in the middle of the retina, the fovea, there are no or only very few rod cells which react to low brightness. Thus, if an attempt is made to look at the marking, so that the marking is imaged on the fovea, it is difficult to recognize the marking or it is not seen at all, since the brightness is not sufficient to excite the cone cells arranged in the fovea. This is particularly the case if the fluorescent layer is additionally covered by a film of paint, so that the floor marking no longer glows as brightly. Furthermore, problems occur particularly if the floor markings have been in the dark for an extended period of time, that is to say in the case of night flights or after the first time operation is commenced in the morning. The problems are further exacerbated if the floor markings only have a small width. In this case, the triangles would have to take up the entire width of the floor marking, so that likewise the recognition of them is worse.
However, the abovementioned problems do not only occur in the airplanes mentioned for the explanation, although this case is particularly important. Similar problems can also occur in different means of transportation or dark rooms, for example cinemas.